JP2007302356A - Paper feeder, original feeder having the same, and image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feeder in which sheets are not fed in a skewed manner even when the sheets of different size in the width direction are set on a tray in an overlapping manner, and the sheets can be fed constantly in a normal posture even when sheets of the different width size are stacked on the tray in a mixed manner. <P>SOLUTION: In the paper feeder, a pickup roller means is arranged above a tray for stacking sheets, and a paper feed roller means is arranged on a fore end of the paper feed direction, respectively. The pickup roller means comprises main roller means 21a, 21b and auxiliary roller means 22a, 22b arranged above the tray with a distance from each other in the sheet width direction. At least the auxiliary roller means are arranged in an elevating/lowering manner between the retracted position above the tray and the operating position to be engaged with the sheets on the tray. A control means for controlling the movement of the auxiliary roller means between the retracted position and the operating position is provided. The control means shifts the auxiliary roller means from the retracted position to the operating position according to the side edge position of the sheets from the paper feed roller means and/or the sheet fore end posture. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sheet feeding device that separates sheets stacked on a tray one by one and feeds them into various apparatuses. For example, when automatically feeding a document sheet onto a platen of an image reading apparatus, The present invention relates to a sheet feeding device capable of feeding out sheets on a tray in a correct posture, a document feeding device using the same, and an image reading device.

  In general, this type of sheet feeding device stacks and stores sheets such as documents on a sheet feeding tray arranged in a substantially horizontal direction, and feeds the sheet from a top sheet by a pickup roller arranged above the tray, and arranges the sheet at the leading end of the tray. Widely used as a device that feeds the paper separated one by one by a paper feed roller. For example, in Patent Document 1, a pick-up roller is disposed above and below a tray on which sheets are stacked, the uppermost sheet on the tray is fed out by this roller, and the uppermost sheet is separated by a paper feed roller disposed at the front end of the tray. An apparatus for feeding to a registration roller on the downstream side is disclosed.

Normally, the pickup roller and the paper feed roller are arranged at a distance in the front and back in the paper feeding direction at the center of the sheet so that the sheet fed out by engaging with the center of the sheet on the tray does not tilt in the width direction. Yes. For this purpose, a side guide is provided on the tray for aligning the sheets on the basis of the center or on one side. The pickup roller has an arm member supported on a rotation shaft of the paper feed roller by a spring clutch that can be contracted and contracted in the rotation direction, and a pickup roller is mounted on the tip of the arm member. In this spring clutch, when the rotation shaft rotates in the paper feeding direction, the spring loosens, and the roller at the tip of the arm member descends from the standby position above the tray by its own weight and engages with the sheet, and when the rotation shaft rotates in the reverse direction. The spring is contracted to rotate the arm member integrally with the rotation shaft, and the roller is lifted from the sheet on the tray and retracted to the standby position.
Japanese Examined Patent Publication No. 6-20956 (FIG. 2)

  As described above, when the sheets stacked on the tray are sequentially fed from the uppermost sheet by the pickup roller and separated and fed one by one between the sheet feeding roller and the separating member, the sheet fed by the pickup roller tends to be a problem. Or there is a problem of wrinkles. This is because such a problem occurs when the sheet is inclined and set on the tray because the pickup roller and the sheet feeding roller are arranged at the center in the width direction of the sheet on the tray. Therefore, conventionally, a side guide member for regulating the side edge in the width direction of the sheet is provided on the tray so that the pickup roller and the paper feed roller are located at the center in the width direction of the sheet.

  However, if sheets of various sizes are stacked and set on the tray, the sheet feeding roller and the pickup roller cannot be arranged at the correct position in the center in the sheet width direction. For example, when a JIS standard A3 size sheet and an A4 size sheet are mixed on top and bottom and set on a tray, the A3 size sheet is fed out in the correct posture, but the A4 size sheet may be fed out at an angle. This is because the pick-up roller and the paper feed roller are located on either side of the width direction so that the sheet fed out is skewed out to the left or right, and if it is buffered with the guide member on the conveyance path, the wrinkle is distorted. May occur or be destroyed.

  Therefore, according to the present invention, even when sheets of different width sizes are set on the tray, they are not skewed and fed, and even when sheets of different width sizes are mixedly loaded on the tray, they are always fed in the correct posture. The main problem is to provide a paper feeding device capable of feeding. Another object of the present invention is to provide a document feeding apparatus capable of feeding a document sheet on a tray to a predetermined reading position in a correct posture when reading a document image, and an image reading apparatus using the document feeding apparatus. .

  The present invention adopts the following configuration in order to solve the above problems. In the present invention, the pick-up roller means and the paper feed roller means are generically referred to as a roller means such as a roller and a belt that transfer a sheet to the downstream side by a frictional force. Therefore, in the present invention, the pickup roller means is disposed above the tray on which the sheets are stacked, and the sheet feeding roller means is disposed at the leading end in the sheet feeding direction. The pickup roller means is composed of main roller means and auxiliary roller means arranged at a distance in the sheet width direction on the tray, and at least the auxiliary roller means is associated with the retracted position above the tray and the sheet on the tray. It is arranged so that it can move up and down between the operating positions.

  Further, a control means for controlling the movement of the auxiliary roller means between the retracted position and the operating position is provided, and the control means is responsive to the side edge position of the sheet from the paper feeding roller means and / or the sheet leading edge posture. The auxiliary roller means is configured to move and shift from the retracted position to the operating position. With this configuration, when sheets having different width sizes are set on the tray in an overlapping manner, for example, when feeding a sheet having a predetermined size or less, the main roller means and the auxiliary roller means are fed, or When the leading edge of the sheet fed from the sheet feeding roller means is inclined, the trailing edge of the sheet is fed by the main roller means and the auxiliary roller means. With such a configuration, the sheet fed downstream from the paper feed roller means does not tend to be fed or is fed to the downstream side of the apparatus in a correct posture with its inclination corrected.

  The control means is configured as follows, for example. In the first method, sensor means for detecting the side edge of the sheet is arranged downstream of the sheet feed roller means to detect the length in the width direction of the sheet, and the auxiliary roller means described above is detected by a signal from this sensor means. Shifting from the retracted position to the operating position. In the second method, sensor means for detecting the leading edge of the sheet is disposed downstream of the sheet feeding roller means, and the skew of the leading edge of the sheet is detected by this sensor means. When skew occurs, the rear end of the sheet is added to the main roller means and kicked by the auxiliary roller means. The former prevents sheet skew, and the latter corrects sheet skew. In either case, the sheet can be fed to the downstream processing position in the correct posture.

  The above-mentioned auxiliary roller means may be arranged at one place in the sheet width direction, but can also be arranged at a plurality of places. In this case, the auxiliary roller means is separated by a distance in the sheet width direction on the tray. A plurality of rollers are arranged, and the plurality of rollers are selectively shifted from the retracted position to the operating position by a signal from the sensor means for detecting the side edge of the sheet separated and fed by the paper feed roller means. To be configured.

  The above-described tray is provided with a side guide member for regulating the position of the side edge on one side of the sheet, and sheets having different width sizes are aligned and set on the basis of this guide member. The main roller means is disposed at a substantially central portion in the width direction of the predetermined size sheet on the tray, and the auxiliary roller means is disposed between the side guide member and the main roller means.

  The paper feed roller means and the registration roller means arranged on the downstream side of the paper feed roller means are connected to a drive motor capable of forward and reverse rotation so as to drive and rotate in a reciprocal manner. A support arm for supporting the main pickup roller means and the auxiliary roller means is attached to each of the drive shafts for rotationally driving the paper feed roller means via a spring clutch, and drive transmission from the drive shaft is transmitted to the spring clutch means. Clutch means for engaging and disengaging is provided. Thus, the main roller means and the auxiliary roller means can be selectively shifted from the retracted position to the operating position by ON / OFF control of the clutch means.

  Next, a document feeder according to the present invention includes a paper feed tray on which a document is placed and set, pickup roller means for sequentially carrying out document sheets on the paper feed tray, and one sheet from the pickup roller means. Paper feed roller means for separating and feeding each sheet, registration roller means for aligning the leading edge of the original sheet from the paper feed roller means, and a carry-in roller for feeding the original sheet from the registration roller means to a predetermined reading position And an unloading roller for unloading the original sheet from the reading position, and a discharge roller for unloading the original sheet from the unloading roller onto the discharge tray.

  The pick-up roller means comprises a main roller means and an auxiliary roller means arranged at a distance in the sheet width direction on the tray, and at least the auxiliary roller means includes a retracted position above the tray, a sheet on the tray, It is provided so as to be movable up and down with respect to the operating position to be engaged. In view of this, a control means for controlling the movement of the auxiliary roller means between the retracted position and the operating position is provided, and the control means is responsive to the side edge position of the sheet from the paper feed roller means and / or the sheet leading edge posture. The auxiliary roller means is configured to move and shift from the retracted position to the operating position.

  According to the present invention, a pickup roller means is arranged by a main roller means and an auxiliary roller means above a sheet stacking tray, and this auxiliary roller is set in accordance with the side edge position or the leading edge posture of the sheet fed from the paper feed roller means. Thus, the sheet is shifted from the upper retracted position to the operating position, so that the sheet is not fed in a skewed state. Therefore, even when sheets are set on the tray at an inclination or when sheets having different width sizes are mixedly loaded, the sheets can be separated by the sheet feeding roller and fed into the apparatus in a correct posture.

  In this case, the side edge position on the leading end side of the sheet fed from the sheet feeding roller is detected by the sensor means. For example, an irregularly sized sheet is kicked at the trailing edge of the sheet by the auxiliary roller means in addition to the main roller means. Even when the roller means is offset from the center of the sheet, it is not inclined and fed, and the skewed sheet is skewed by detecting the leading edge posture on the downstream side of the paper feed roller. Can be corrected by kicking the trailing edge of the sheet with auxiliary roller means, and the sheet can always be fed in a correct posture with a simple configuration.

  Furthermore, by arranging a plurality of auxiliary roller means in the sheet width direction, a certain sheet is kicked and conveyed by a plurality of auxiliary rollers according to the sheet width direction size, and a certain sheet is kicked by one auxiliary roller. If configured, even if sheets of a wider range of sizes are mixed, it can be fed in a normal posture.

  The present invention will be described in detail below based on the preferred embodiments shown in the drawings. FIG. 1 is an explanatory view showing a cross section of a main part of a paper feeding apparatus according to the present invention. FIG. 2A is an explanatory diagram showing the planar configuration of the tray, and FIG. 2B is an explanatory diagram of control data for setting the operating condition of the auxiliary roller. FIG. 3 is an explanatory view of a drive mechanism of the pickup roller means, and FIG. 4 is an explanatory view of a main part showing a support structure of the auxiliary roller.

  As shown in FIG. 7, the sheet feeding apparatus A includes a tray 1 on which sheets are placed, pickup roller means 2 for sequentially feeding sheets on the tray, and sheets fed by the pickup roller means 2 one by one. A sheet feeding roller unit 3 for feeding separately and a registration roller unit 4 arranged on the downstream side of the sheet feeding roller unit 3 are provided. The tray 1 is composed of a tray member for stacking and storing ordinary sheets, and the tray 1 is provided with a side guide 11 for placing and setting the sheets in a predetermined posture. The side guide 11 is configured by a one-side regulation guide that is fixed to the tray 1 and feeds one side edge of the sheet, or a pair of left and right regulation guides that are movable in the width direction of the tray member. In the former, sheets of different sizes are set as one-side reference, and in the latter, the sheet is set as a sheet-feeding reference based on the center reference.

  The illustrated one shows a case where the paper feed reference is the center reference X1. As shown in FIG. 2A, a pair of left and right side guides 11a and 11b are attached to the tray 1 so as to be movable in the width direction with reference to a paper feed reference (X1 in the drawing) at the center of the tray. The side guides 11a and 11b are connected on the back side of the tray 1 so as to approach and separate from each other by the same amount around the paper feed reference X1. For example, various structures are known in which, for example, rack gears provided on both guides are connected by a pinion arranged on a tray. In either one of the side guides 11a and 11b, a side sensor St1 for detecting the position is arranged. The side sensor St1 is configured by a sensor array or a slide sensor in which a plurality of sensors are arranged in the tray width direction. The tray 1 has an empty sensor St2 arranged in a normal configuration.

  Accordingly, sheets are stacked on the tray 1 so as to be aligned with the left and right side guides 11a and 11b, and the maximum sheet size is detected by the side sensor St1. At this time, when sheets of a plurality of sizes having different width sizes are mixedly mounted, the illustrated one is placed according to the sheet side edge of the maximum size width in the apparatus specification. That is, the user sets a plurality of sheets having different width sizes on the tray 1 according to the end face (X2 in FIG. 2) of the maximum width sheet. Hereinafter, the end face (X2) of the maximum width sheet is referred to as a set reference.

  The pickup roller means 2 is composed of main roller means 21 (21a, 21b) and auxiliary roller means 22 (22a, 22b) disposed at a distance in the sheet width direction on the tray 1. In the drawing, the main roller means 21 is disposed at the center of the tray (X1 in FIG. 2) and the auxiliary roller means 22 is disposed at the side on the set reference X2 side because of the center reference. The main roller means 21 may be constituted by a single roller having an appropriate width, but the illustrated one is constituted by two rollers 21a and 21b. Similarly, the auxiliary roller means 22 may be a single roller, but is composed of two rollers, a first auxiliary roller 22a and a second auxiliary roller 22b. The reason will be described later. In the main roller means 21, two rollers are arranged at equal intervals on the paper feed reference (center reference) X1 of the tray 1, and the auxiliary roller means 22 is spaced from the sheet side edge on the set reference X2 side. (See FIG. 2). The first and second auxiliary rollers 22a and 22b are disposed downstream of the main roller means 21 in the sheet feeding direction.

  The main roller means 21 and the auxiliary roller means 22 are disposed so as to be movable up and down between an operating position that engages with the uppermost sheet above the tray 1 and a retracted position that is spaced upward from the sheet. This is because when a sheet is set on the tray 1, the sheet is retracted to the upper retracted position, and when the set sheet is fed out, the sheet is positioned at the operating position. The lifting mechanism will be described with reference to FIGS. The main roller means 21 is swingably supported on the rotary shaft 5 by an arm-like support member 23 (hereinafter referred to as a first support arm), and the first auxiliary roller 22a is supported on the rotary shaft 5 by an arm-like support member 24a (hereinafter referred to as a second support arm). The second auxiliary roller 22b is supported on the rotary shaft 5 by an arm-like support member 24b (hereinafter referred to as a third support arm) so as to be swingable. A drive motor M1 is connected to the rotating shaft 5 as will be described later.

  The base end of the first support arm 23 is loosely supported on the rotary shaft 5, and main roller means 21 a and 21 b are axially supported on the tip of the arm. A spring end portion of a spring clutch 51 wound around the rotary shaft 5 is frictionally engaged with the base end portion of the arm, and the spring clutch 51 is rotated in the sheet feeding direction of the rotary shaft 5 (clockwise in FIG. 3). It is configured to loosen and to contract in rotation in the counter-feeding direction. Accordingly, the spring clutch 51 is loosened by the rotation of the rotating shaft 5 in the sheet feeding direction, and the first support arm 23 is swung clockwise by the weight of the first support arm 23. Then, it abuts against a stopper member (not shown) and is held in that position. The rotary shaft 5 is provided with a paper feed roller means 3 via a one-way clutch 53, and the rotation of the rotary shaft 5 is transmitted from the pulley 54 to the main roller means 21a, 21b via the clutch 53 via the transmission belt 25. It is like that. The one-way clutch 53 is configured to transmit the rotation of the rotating shaft 5 in the sheet feeding direction to the sheet feeding roller means 3 and the main roller means 21.

  The second and third support arms 24 are loosely supported at their base ends by bearing sleeves 55a and 55b fitted to the rotary shaft 5, and the first auxiliary roller 22a is axially supported at the tip of the second support arm 24a. Similarly, the second auxiliary roller 22b is axially supported at the tip of the third support arm 24b. A spring clutch 56a is provided between the bearing sleeve 55a and the second support arm 24a. The clutch 56a is configured to be loosened when the bearing sleeve 55a is rotated in the paper feeding direction, and to be contracted when the bearing sleeve 55a is rotated in the anti-paper feeding direction. Yes.

  Similarly, a spring clutch 56b having the same configuration is provided between the third support arm 24b and the bearing sleeve 55b. Therefore, an electromagnetic clutch Mc1 is provided between the bearing sleeve 55a and the rotary shaft 5, and an electromagnetic clutch Mc2 is provided between the bearing sleeve 55b and the rotary shaft 5. The rotation of the rotary shaft 5 is transferred to the bearing sleeves 55a and 55b. It is designed to communicate selectively. The rotation of each sleeve is transmitted to the first auxiliary roller 21a by the gear train G1 and to the second auxiliary roller 22b by the gear train G2.

  Therefore, by rotating the electromagnetic clutches Mc1 and Mc2 on and off, the rotation of the rotary shaft 5 in the paper feeding direction is transmitted from the gears G1 and G2 to the auxiliary rollers 22a and 22b via the sleeves, and the spring clutches 56a and 56b are simultaneously relaxed. As a result, the second and third support arms 24 are swung in the clockwise direction in FIG. Further, the rotation of the rotating shaft 5 in the counter feed direction is transmitted to each sleeve and the spring clutches 56a and 56b are tightened to swing the second and third support arms 24 counterclockwise in FIG. It can be abutted and held in that position.

  A paper feed roller 3 is fitted and supported on the rotary shaft 5 via a one-way clutch 53, and the rotation of the rotary shaft 5 in the paper feed direction is transmitted to the roller 3. The sheet feeding roller 3 is disposed substantially at the center of the sheet width, and separates the sheets one by one from the separation roller 13 that is in pressure contact therewith. The separation roller 13 has a smaller friction coefficient than the sheet feeding roller and is larger than the friction coefficient between the sheets, and is driven and rotated in a stationary state or in the opposite sheet feeding direction. The registration rollers 4 are arranged at intervals on the downstream side of the sheet feeding roller configured as described above, and the leading edges of the sheets separated and fed by the sheet feeding roller are abutted and aligned.

  In other words, the leading edge of the sheet fed by the sheet feeding roller 3 is brought into contact with the nip point of the stopped registration roller 4 to bend the sheet, and then the sheet is pulled out from the stopped sheet feeding roller 3 to correct the sheet skew. To do. A paper feed guide 15 (15a, 15b) is arranged between the paper feed roller 3 and the registration roller 4 so as to guide the sheet.

  The registration roller 4 is connected to a drive motor M1 that can be rotated forward and backward so that when one of the registration rollers 4 rotates contrary to the paper feed roller 3, the other stops. As shown in FIG. 3, the rotation of the drive motor M1 is transmitted to the rotating shaft 4d via the belt V1, and only one rotation of the rotating shaft 4d (rotation in the counter feed direction of the rotating shaft 5) is rotated by the spring clutch 4b. The transmission is transmitted to the gear train G3, and the drive rotation shaft 4c of the registration roller 4 is connected to the gear train G3.

  In the present invention, the pickup roller means 2 comprises the main roller means 21 (21a, 21b) and the first and second auxiliary roller 22 means (22a, 22b) as described above, and the first and second auxiliary rollers. In order to control the means 22, sensor means So for detecting the sheet is arranged in the paper feed guide 15. This sensor means So is arranged so as to detect the side edge in the sheet feeding orthogonal direction of the sheet fed on the guide 15 or to detect the leading edge in the sheet feeding direction. FIG. 2 shows sensor means So for detecting the side edge in the sheet feeding orthogonal direction, and a plurality of sensors So1, So2, So3, So4 are arranged in the width direction and fed by the sheet feeding roller 3 as shown in the figure. The side edge position from the set reference X2 is detected.

  2, the sensor So4 detects all the sheet side edges of A4, B4, and A3, the sensors So1 and So2 detect the B4 and A3 size sheet side edges, and the sensor So3 detects A3. The sheet is arranged at a position for detecting the size side edge. Sensors So1 and So2 identify sheet side edges of other sizes (not shown) such as legal and letter sizes. Thus, the sheet side edge positions of different width sizes aligned with the set reference X2 are detected by the plurality of sensors So1 to So4. The sensor means So may be composed of one line sensor. Although not shown, when detecting the leading edge of the sheet in the sheet feeding direction, at least two sensors are arranged at a distance in the sheet width direction, and the skew (bend) of the sheet fed by the sheet feeding roller 3 is arranged. Is detected.

  Therefore, the present invention detects the position of the side edge in the width direction of the sheet fed to the sheet feeding guide 15 by the sheet feeding roller means 3 by the sensor means So, and if there is a possibility that the sheet will be bent (skew), the above-mentioned. The auxiliary roller means 22 is moved from the retracted position to the operating position so as to apply a conveying force to the trailing edge of the sheet. The control configuration will be described with reference to the block diagram of FIG. The apparatus in FIG. 1 is a paper feeding device of a document feeding device, which will be described later, connected to the image forming apparatus, and is connected to a control unit of the image forming apparatus. The control unit of the document feeder includes a control CPU 17, which is connected to a ROM 18 that stores a control program for paper feeding operation and a RAM 19 that stores control data.

  The control CPU 17 is connected to the side sensor St1 and the sensor means So (sensors So1 to So4) so as to transmit respective detection signals. The control CPU 17 is connected to issue a command signal to the drive circuit of the drive motor M1, and at the same time, is connected to control the electromagnetic clutches Mc1 and Mc2 to be turned on and off. In the control program, the auxiliary rollers 22a and 22b are moved to the operating position according to the sheet side edge position detected by the sensor means So, and the rear end of the sheet on the tray 1 is fed out together with the main roller means 21. To do.

  The control CPU 17 is provided with a memory table (RAM) 19 for operating the auxiliary rollers 22a and 22b when the main roller 21 has a width that is easy to skew the sheet. The table 19 stores data for controlling the electromagnetic clutch Mc1 connected to the auxiliary roller 22a and the electromagnetic clutch Mc2 connected to the auxiliary roller 22b as shown in FIG. 2B, for example. FIG. 2 shows an example in which the maximum size of the sheet set on the tray 1 is JIS standard A3. The maximum size is B4, and other control data corresponding to the apparatus specifications is prepared in the RAM 19.

  Referring to FIG. 2B, when the sheet fed from the sheet feeding roller means 3 is A3, the sensors So1 to So4 are all in the ON state. At this time, the first and second auxiliary rollers 22a and 22b are in the retracted position. Only the main rollers 21a and 21b feed the sheet. In this case, the main rollers 21a and 21b are in a positional relationship of L1 = L2 in the drawing, and are fed out without biasing the center of the sheet. Next, when the sheet width is B4 size, So3 = OFF, and the other sensors So1, So2, So4 are all turned on. At this time, the first auxiliary roller 22a is operated and the second auxiliary roller 22b is positioned at the standby position. Let

  In this case, L1 <L2 shown in the figure, and the main rollers 21a and 21b are slightly biased away from the set reference X2 from the center of the sheet. When the sheet width is A4, So4 = ON, and the other sensors So1, So2, So3 are all in the OFF state. At this time, the first and second auxiliary rollers 22a, 22b are operated. In this case, L1 << L2 shown in the figure, and the main rollers 21a and 21b deviate from the center of the sheet and greatly deviate in a direction away from the set reference X2.

  The sheet feeding operation executed by the control CPU 17 will be described with reference to FIGS. 5 and 6. Sheets having different width sizes are set on the tray 1 in the state shown in FIG. Upon receiving the paper feed instruction signal, the control CPU 17 retracts the gate stopper 14 from the tray, and then drives the drive motor M1 to rotate in the paper feed direction. With this rotation of the motor, the rotating shaft 5 rotates clockwise in FIG. 3 and the spring clutch 51 is loosened. The first support arm 23 supported by the shaft 5 swings and rotates clockwise by its own weight, and is attached to the main support arm 23 attached thereto. The roller means 21a and 21b are lowered to the operating position in the state shown in FIG. At the same time, the rotation of the rotary shaft 5 is transmitted to the rollers 21a and 21b by the transmission belt 25. In this state, the main roller means 21 a and 21 b feed the uppermost sheet on the tray toward the paper feed roller 3. The sheet fed in this way is separated into one sheet between the sheet feeding roller and the separation roller 13 and sent to the sheet feeding guide 15.

  The side edge position of the sheet sent to the paper feed guide 15 is detected by the sensor means So, and the control CPU 17 determines whether or not to operate the first and second auxiliary rollers 22a and 22b by the status signal of the sensor means So. to decide. This determination is made based on the memory table 19 described above, and when the first and second auxiliary rollers are operated, the electromagnetic clutch Mc1 and / or the clutch Mc2 is turned “ON”. Then, the bearing sleeves 55a and 55b rotate clockwise in FIG. 3, the spring clutches 56a and 56b loosen, and the second and third support arms 24a and 24b supported by the sleeve swing and rotate clockwise with their own weight. The first and second auxiliary rollers 22a and 22b attached to the lowering position are lowered to the operating position in the state of FIG. The first and second auxiliary rollers 22a and 22b receive the rotation of the bearing sleeves 55a and 55b by the gears G1 and G2 and rotate in the sheet feeding direction, and feed the sheet downstream together with the main roller means 21.

  Next, when the leading edge of the sheet reaches the registration roller 4, the control CPU 17 stops the drive motor M1 after a predetermined time from the detection signal of the registration sensor Sr1. At this time, the leading edge of the sheet comes into contact with the registration roller 4 and bends to the state shown in FIG. 6C to correct the skew of the leading edge. Next, the control CPU 17 obtains a paper feed timing signal and drives the drive motor M1 to rotate in the reverse paper feed direction. Then, the rotating shaft 5 rotates counterclockwise in FIG. 3, and the spring clutch 51 is tightened to rotate the first support arm 23 counterclockwise. As a result, the main roller means 21 moves from the operating position to the retracted position (the state shown in FIG. 5A). At the same time, when the control CPU 17 turns on the electromagnetic clutches Mc1 and Mc2, the auxiliary roller 22 moves from the operating position to the retracted position in the same way as the main roller, and returns to the state shown in FIG. Prepare for.

  Although the case where the main roller means 21 is returned to the retracted position by the above operation has been described, control may be performed so that the next sheet is fed in a state where the main roller means 21 is located at the operating position. On the other hand, when the drive motor M1 rotates in the counter feed direction, the registration roller 4 connected thereto rotates in the direction of the arrow shown in FIG. 6D, and feeds the sheet downstream. At this time, the sheet feeding roller means 3 prevents the subsequent sheet from being fed in a stopped state.

  When the main roller means 21 is located in a distance relationship deviated from the center of the sheet (sheet feeding reference X) in the process of feeding the sheet from the tray 1 to the sheet feeding roller means 3 by the pickup roller means 2, the auxiliary roller The means 22 can apply a conveying force to the sheet to prevent skewing and feed the sheet in a normal posture. Further, the sheet is applied by the first and second auxiliary rollers 22a and 22b depending on the degree of deviation of the distance relationship. It is possible to feed the sheet in a more accurate posture by adjusting the conveyance force.

  Next, the configuration of the document feeding device B and the image reading device C incorporating the above-described paper feeding device A will be described. FIG. 7 shows the overall configuration of the image reading apparatus C and the document feeding apparatus B mounted on the image reading apparatus C, and the apparatus shown in FIG. The apparatus shown in FIG. 7 includes an image forming apparatus B and an image reading apparatus C disposed on the image forming apparatus. The image reading apparatus C incorporates the above-described paper feeding apparatus A.

  Although not shown, the image forming apparatus B includes a printing unit such as a printing drum, and forms an image on a sheet fed from the paper feeding unit. Various printing means are known. For example, a latent image is formed on an electrostatic drum by an optical head, and ink such as toner is attached to the image and transferred onto a sheet for heat fixing, directly on the sheet. A structure for forming an image with an inkjet nozzle is known, and any of them can be employed.

  The image reading apparatus C includes a platen 30 for setting an original sheet, a carriage 31 for scanning and reading the original sheet on the platen 30, and a reading means having a photoelectric conversion means 32 built in the carriage. The illustrated one is provided with a second platen 33 for reading an image in the process of moving the original sheet. A document feeder A for feeding a document is mounted on the second platen.

  The document feeder A incorporates the above-described sheet feeder A. The structure of the document feeder A will be described in detail with reference to FIG. 1. Above the platen 33, the sheet feed tray (the tray) 1, the sheet discharge tray 34, and the sheet feeder A U-shaped transport path 35 extending from the tray 1 to the paper discharge tray 34 through the second platen 33 is provided. On the paper feed tray 1, the pickup roller means 2 and the paper feed roller means 3 are provided in the above-described configuration. The above-described sensor means So is disposed in the paper feed guide 15 that forms the transport path 35, and the registration roller 4 is disposed downstream thereof. As described above, the original sheet fed from the tray 1 is fed to the registration roller 4. A lead roller 36 for feeding the original sheet to the second platen 33 at a predetermined speed and a lead sensor Sr2 for detecting the leading edge of the sheet are disposed on the downstream side of the registration roller 4 at the illustrated position.

  A backup roller 37 is disposed on the second platen 33 and guides the original sheet fed by the lead roller 36 from above the platen 33. A carry-out roller 38 is provided on the downstream side of the platen 33 to carry out the original sheet from the platen. A paper discharge roller 39 is provided on the downstream side of the carry-out roller 38 and carries the original sheet from the platen 33 onto the paper discharge tray 34. In addition, a circulation path 40 is provided that guides the original sheet from the paper discharge roller 39 to the registration roller 4 by switching back. The read roller 36, the backup roller 37, the carry-out roller 38, and the paper discharge roller 39 are connected to the second drive motor M2, and each conveys the original sheet at the same peripheral speed. Reference numeral 41 denotes a platen cover that covers the platen 30.

  Therefore, the control CPU 17 feeds the original sheet on the tray 1 from the registration roller 4 to the downstream read sensor Sr2 by rotating the drive motor M1 forward and backward as described above. The control CPU 17 drives the second drive motor M2 by the tip detection signal from this sensor. This driving is set according to the reading conditions of the original sheet (color image, monochrome image, etc.), and the read roller 36 is rotated at this speed to pass the original sheet over the second platen 33 at a predetermined speed. At the same time, the control CPU 17 transfers the tip detection signal of the read sensor Sr2 to the data processing unit of the image reading means (the photoelectric conversion means), and uses it as a reference for the reading start position. When reading the front and back surfaces of the original sheet, the paper discharge roller 39 is reversed to reverse the original sheet and guided to the registration roller 4 from the circulation path 40. This document sheet is again sent to the lead roller 36, and after the image of the back side of the document is read by the platen 33, the document sheet is stored in the paper discharge tray 34.

It is sectional drawing which shows the paper feeder of this invention. (A) is explanatory drawing which shows the planar structure of the tray in the apparatus of FIG. 1, (b) is explanatory drawing of the control data which sets the operating condition of an auxiliary roller. It is explanatory drawing of the drive mechanism of the pick-up roller means in the apparatus of FIG. It is principal part explanatory drawing which shows the support structure of the auxiliary roller in the apparatus of FIG. FIGS. 2A and 2B are explanatory diagrams illustrating a sheet feeding state in the apparatus of FIG. 1, in which FIG. 1A illustrates a state in which a sheet is set, and FIG. FIGS. 2A and 2B are explanatory diagrams illustrating a sheet feeding state in the apparatus of FIG. 1, in which FIG. 1C is an explanatory diagram illustrating a state in which a sheet is fed to a registration roller, and FIG. . FIG. 2 is an explanatory diagram illustrating an entire document feeding device including the paper feeding device of FIG. 1. It is a block diagram which shows the control means of the apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tray 2 Pickup roller means 3 Feed roller means 4 Registration roller 11 Side guide 13 Separating roller 14 Gate stopper 15 Feed guide 21a Main roller means 21b Main roller means 22a First auxiliary roller means 22b Second auxiliary roller means 23 First Support arm 24a Second support arm 24b Third support arm 32 Photoelectric conversion means (image reading means)
33 Second platen 34 Paper discharge tray 55a Bearing sleeve 55b Bearing sleeve So Sensor means St1 Side sensor X1 Paper feed standard (center standard)

Claims (9)

A tray for placing sheets;
Pick-up roller means for sequentially carrying out the sheets on the tray;
A sheet feeding device comprising sheet feeding roller means for separating and feeding sheets from the pickup roller means one by one,
The pickup roller means is composed of main roller means and auxiliary roller means arranged at a distance in the sheet width direction on the tray,
At least the auxiliary roller means is provided to be movable up and down between a retracted position above the tray and an operating position that engages with a sheet on the tray.
Control means for controlling the movement of the auxiliary roller means between the retracted position and the operating position is provided,
The control unit moves and shifts the auxiliary roller unit from the retracted position to the operating position in accordance with a side edge position of the sheet from the sheet feeding roller unit and / or a sheet leading edge posture. The control means is disposed downstream of the paper feed roller means and shifts the auxiliary roller means from the retracted position to the operating position by a signal from a sensor means for detecting a side edge of the sheet from the paper feed roller means. The sheet feeding device according to claim 1, wherein: The control means is arranged downstream of the paper feed roller means and shifts the auxiliary roller means from the retracted position to the operating position by a signal from a sensor means for detecting the leading edge posture of the sheet from the paper feed roller means. The paper feeding device according to claim 1. The auxiliary roller means is composed of a plurality of rollers arranged at a distance in the sheet width direction on the tray, and the plurality of rollers detect a side edge of the sheet separated and fed by the paper feed roller means. The sheet feeding device according to claim 2, wherein the sheet feeding device is selectively shifted from the retracted position to the operating position by a signal from the sensor means. The tray is provided with a side guide member for regulating the position of the side edge on one side of the sheet,
The main roller means is disposed substantially in the center in the width direction of the predetermined size sheet on the tray,
5. The sheet feeding device according to claim 1, wherein the auxiliary roller unit is disposed between the side guide member and the main roller unit. A drive motor capable of forward and reverse rotation is coupled to the paper feed roller means,
On the downstream side of the paper feed roller means, a registration roller means for aligning the leading edge of the sheet is disposed,
The drive motor is connected to the paper feeding roller means and the registration roller means so as to transmit driving reciprocally,
Support arms for supporting the main pickup roller means and the auxiliary roller means are attached to the drive shafts for rotating the paper feed roller means via spring clutches, respectively.
6. The paper feeding device according to claim 1, wherein the spring clutch means is provided with clutch means for engaging / disengaging drive transmission from the drive shaft. A paper feed tray on which documents are placed and set;
Pick-up roller means for sequentially carrying out the original sheets on the paper feed tray;
Paper feed roller means for separating and feeding sheets from the pickup roller means one by one;
Registration roller means for aligning the leading edge of the original sheet from the paper feed roller means;
A carry-in roller for feeding a document sheet from the registration roller means to a predetermined reading position;
An unloading roller for unloading the original sheet from the reading position;
A paper discharge roller for carrying out the original sheet from the carry-out roller onto a paper discharge tray,
The pickup roller means is composed of main roller means and auxiliary roller means arranged at a distance in the sheet width direction on the tray,
At least the auxiliary roller means is provided to be movable up and down between a retracted position above the tray and an operating position that engages with a sheet on the tray.
Control means for controlling the movement of the auxiliary roller means between the retracted position and the operating position is provided,
The control means moves and shifts the auxiliary roller means from the retracted position to the operating position in accordance with the side edge position of the sheet from the sheet feeding roller means and / or the sheet leading edge posture. . The pickup roller means, the paper feed roller means, and the registration roller means are connected to a first drive motor capable of forward and reverse rotation,
The carry-in roller, the carry-out roller, and the paper discharge roller are connected to a second drive motor,
The auxiliary roller means constituting the pickup roller means is configured to move up and down between the retracted position and the operating position by the rotation of the first drive motor,
8. The document feeding device according to claim 7, wherein the rotation of the first drive motor is transmitted to the auxiliary roller means through an electromagnetic clutch to shift the shift from the retracted position to the operating position. . A reading platen;
Image reading means for optically reading a document image on the reading platen;
A document feeder for feeding a document sheet onto the reading platen,
An image reading apparatus having the configuration according to claim 7 or 8.

Images